'94 R1100GS That damn knocking sound?

[rossco@snet.net]

Fellow oil heads please help me locate and stop that knocking sound before they take me to the looney bin. Last Xmas I purchased this '94 R1100GS with 46,000 miles and a knocking sound. It's my first boxer engine and I'm not familure with the sounds although I'm getting used to them after 4k miles.

The knocking sound is coming from the right cylinder, back side. It was only noticeable after a fully warmed engine and with little to no load such as idling or running along in 2nd or 3rd gear. To make a long story short; on advice from a 20 year Beemer mechanic I replaced both cam chain tensioners-no change, based on a YouTube video with the same noise I replaced the throttle body bushings-no change, pulled head and inspected cams, push rods, etc.-nothing loose or worn, of course the very first thing I did was check valve gaps and they were perfect but after reading on a forum later that the rocker arm can make the same noise I went back and checked the end float rocker gap. It was well within spec but I tightened it up to the lesser side and the noise is not so loud or present so I tightened it up even more to very close to the minimum gap (0.002 in) and no change.

In summary, now it?s more like a rattle sound during idle so I?ve reduced it?s presence and volume but it is still there driving me crazy. I just want it to be like it?s twin on the left so I?m not wondering when it?s going to break down. Could it be timing? The bike has an after-market exhaust with a Techlusion fuel control box. Any other ideas? Maybe it?s in my head!

New MOA member,
Rossco

 

[20774]

Rossco -

Welcome to the forum! About all I can say is it's in someone's head!!

BTW...no biggee but it looks like you composed your post in a word processor and then copy-pasted it here. Sometimes, a few of the punctuation marks used in the word processor don't map over well here. You can see the "?" in your post. Just thought I'd throw that out there.

 

[lkchris]

First R1100GS was probably 1994, not 1984.

 

[happy wanderer]

Welcome here Rossco. Some questions:
- Before you pulled the head did you check the compression on both sides?
- When you pulled the head did you also pull the cylinder and examine it and the piston skirts?
- Is there any noticeable oil leaks anywhere around that cylinder?

I had a right side knocking sound on a 96 RT back in 2010 that turned out to be a cracked at the base barrel that had scored the piston on that side. I think this happened when the bike was dropped hot and running by the PO. This is just a guess however since I bought the bike from a consignment shop. We could not surmise any other way it could have happened. The problem presented as a knocking sound on the right hand side only along with compression loss and some oil leaking around the bottom of the cylinder next to the engine casing. Hence these questions...

 

[rossco@snet.net]

Rossco -

Welcome to the forum! About all I can say is it's in someone's head!!

BTW...no biggee but it looks like you composed your post in a word processor and then copy-pasted it here. Sometimes, a few of the punctuation marks used in the word processor don't map over well here. You can see the "?" in your post. Just thought I'd throw that out there.

Yup, I used MS Word. Thanks.

 

[rossco@snet.net]

First R1100GS was probably 1994, not 1984.

Yes, it is a '94 not '84. My son's car is an '84 and that noise is making me confused.

 

[20774]

Yes, it is a '94 not '84. My son's car is an '84 and that noise is making me confused.

Too funny!! Fixed if for you!!

 

[rossco@snet.net]

Welcome here Rossco. Some questions:
- Before you pulled the head did you check the compression on both sides?
- When you pulled the head did you also pull the cylinder and examine it and the piston skirts?
- Is there any noticeable oil leaks anywhere around that cylinder?

I had a right side knocking sound on a 96 RT back in 2010 that turned out to be a cracked at the base barrel that had scored the piston on that side. I think this happened when the bike was dropped hot and running by the PO. This is just a guess however since I bought the bike from a consignment shop. We could not surmise any other way it could have happened. The problem presented as a knocking sound on the right hand side only along with compression loss and some oil leaking around the bottom of the cylinder next to the engine casing. Hence these questions...

No to compression check and no to piston inspection. I only pulled the head off to check the push rods, cams and piston top. I lacked a gasket for the cylinder and compression tool for the rings. There are no oil leaks and the bike has crash bars to protect the engine but I plan to do major maintenance this winter when the snow arrives so I'll pull that cylinder for sure. In the mean time I'll check the compression. Thanks. BTW, my mistake it's a '94.

 

[bc1100s]

In summary, now it?s more like a rattle sound during idle so I?ve reduced it?s presence and volume but it is still there driving me crazy.

As odd as this may sound, my right side rockers start to make a little noise at idle when my oil needs changing. Its inconsistent but that's why I say its odd. Not sure if this will help or serve to confuse the issue even more.

 

[PGlaves]

As odd as this may sound, my right side rockers start to make a little noise at idle when my oil needs changing. Its inconsistent but that's why I say its odd. Not sure if this will help or serve to confuse the issue even more.

Not odd at all. It represents the reduction in viscosity of the oil as it breaks down with use.

 

[dieselyoda]

Does the sound change when you release the clutch lever, fully, at idle? Do you have some clutch free play?

 

[aapasquale]

Does the noise sound strong while in neutral and stop while clutch is engaged or in gear? Some of the comments conflicted and I wanted to clear this up. My 94 R1100RS clutch makes a lot of noise when the bike is warmed up and in neutral. Have been told by more knowledgeable people that it's probably the throw out bearing. Could this be the source of your noise?

 

[rossco@snet.net]

The noise doesn't seem to have any relation to the clutch although there are other noises that most certainly could be. To be very specific, before adjusting the intake rocker arm side to side gap the noise started when engine was fully warmed and during idle or running in low gears. Now, after adjusting intake rocker to minimum gap the sound starts immediately but only during a change in RPM at idle or when coasting in 1st or 2nd gear, a no-load condition, but at resting idle the knocking sound goes away. The knocking sound is much louder than all the other engine noises and it obviously comes from the right side and using a stethoscope to locate the exact origin it's loudest around the intake port.

As for oil, I've checked the level and changed it recently.

Thanks to all for the extra brain power, I want to make a trip to Maine (from CT) before the snow comes but would like to solve this riddle before I go.

 

[dieselyoda]

I have a pretty significant knock at idle when hot and I know I have a flat top rocker. I could care less right now. It runs good, I ride as much as I can and I am probably due for some TLC eventually. Where do you think you are at? Ride it until she breaks or ride until you have some time to get it into it?

 

[rossco@snet.net]

I have a pretty significant knock at idle when hot and I know I have a flat top rocker. I could care less right now. It runs good, I ride as much as I can and I am probably due for some TLC eventually. Where do you think you are at? Ride it until she breaks or ride until you have some time to get it into it?

I've been commuting with it since last March but it won't break which doesn't surprise me. This call for help is part of my planning to take things apart this winter. What is flat on the rocker?

 

[dieselyoda]

I've been commuting with it since last March but it won't break which doesn't surprise me. This call for help is part of my planning to take things apart this winter. What is flat on the rocker?

I have a rocker arm, where it contacts the valve stem, which is flat, that has lost it's convex, meaning it's gone flat and doesn't roll off the stem smoothly. I found it doing a valve adjustment when I felt the feeler gauge hang up. It didn't come out smooth. Of course, it would be on the exhaust as they were all tight first time I did a valve set after getting the bike. That was about 25K miles ago.

I've since done a few valve adjustments and it doesn't seem to get worse and I can't be bothered by a little knock when the bike otherwise runs awesome.

For me, I am notorious at ignoring little problems until they become big ones and I'm sure this winter I am doing a valve job as I can just guarantee that I have worn a pretty severe convex in the valve stem.

I would be rather surprised that you have the same problem as there can be many reasons for your knock. Don't discount the pushrods where they sit into their cups either. It cold also be as bad as a sticking valve so if you are going into it for some needed loving, a really good flashlight and a magnifying glass can be your best friends. Doesn't hurt to take pictures and post them here and ask, "what do you think?"

 

[m_stock10506]

Fellow oil heads please help me locate and stop that knocking sound before they take me to the looney bin.
<snip> ... based on a YouTube video with the same noise I replaced the throttle body bushings-no change
...............
Any other ideas? Maybe it?s in my head!

New MOA member,
Rossco

You say you changed the TB bushings, but did you also replace the TB shaft. The shaft is what usually wears, more than the bushings. If it's making the noise at idle, can you put your hand on the throttle pulley and make the noise stop? If that's what you need there's a guy that makes a TB refurbish kit.

 

[dieselyoda]

You say you changed the TB bushings, but did you also replace the TB shaft. The shaft is what usually wears, more than the bushings. If it's making the noise at idle, can you put your hand on the throttle pulley and make the noise stop? If that's what you need there's a guy that makes a TB refurbish kit.

I'm going to take a SWAG and say the YouTube video was the one I posted and the knock was very distinctly at idle. Just a bit of throttle load and the noise was gone. The solution was TB bushings and shafts and a new Bowden cable that was the entire cable. Mine didn't have the little splitter box mess.

So much stuff on these bikes can make noise that sounds horrific, but still quieter and smoother than the R1200RT Wethead I rode a month ago.

Now I've stepped in it....................

 

[happy wanderer]

I'm going to take a SWAG and say the YouTube video was the one I posted and the knock was very distinctly at idle. Just a bit of throttle load and the noise was gone. The solution was TB bushings and shafts and a new Bowden cable that was the entire cable. Mine didn't have the little splitter box mess.

I think I saw that video and it was a 95 or 96. They didn't have a Bowden box (little splitter box mess) or bowden cables. Just has one long throttle cable that goes to both throttle bodies. Harder to adjust and wander out of adjustment more easily than the Bowden box oilheads.

 

[m_stock10506]

I worked with a buddy this weekend on refurbishing the throttle bodies on his '99 R1100RS. His bike has over 100K miles and he used the TB repair kits from Dan Cata to replace the bushings and the shaft in both left and right TBs. He had that tapping sound at idle and now it's gone. The kits aren't hard to install. The pulley on most of the TBs are pressed on to the shaft instead of held on with a nut. This requires them to be knocked off the shaft - Cata says you can knock it out but it's on there pretty tight so we drilled the end of the old shaft and then it got knocked out easily. The butterfly has to be positioned perfectly on the new shaft or it will not close fully which will screw up your effort to balance the TBs. Just keep the screws a little loose until it's centered and opens and closes properly then tighten it up.

Does the OP have an update on this?